A diagram in the course handout shows that a teacher asks for one developmental clue linking molluscs with annelids. Identify the related structure or process.

Many molluscs and annelids share a trochophore larva, which supports their placement among lophotrochozoan protostomes. This does not mean their adult body plans are identical. This MCQ belongs to the Comparative zoology topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.